Rubber and plastic bonding

ABSTRACT

A dry liquid concentrate mixture is disclosed comprising crumb rubber particles and tall oil, tall oil derivatives or other fatty acids, which may be enhanced by other components, such as modifiers, for use to enhance the properties of parent materials, such as thermoplastic compounding and coatings and elastomers and recycles and asphalt and epoxies and aliphatic urethane.

This is a continuation of application Ser. No. 886,338, filed May 20,1992 now abandoned. BACKGROUND OF PRIOR ART

The present invention relates generally to the utilization of scraptires, and more particularly to the bonding of rubber and plasticmaterial.

DESCRIPTION OF PRIOR ART

Each year there are an estimated 250,000,000 scrap tires discardedthroughout the United States. Unwanted scrap tire piles, scatteredthroughout the country, have been estimated as high as 3 billion units.The poor biodegradability of scrap tires, their tendency to trap gasesand rise to the surface in landfills, the serious fire hazard scrap tirepiles represent, and the breeding environment that unwanted scrap tirepiles offer to disease carrying pests, such as rodents and mosquitos,has caused them to be classified as a serious environmental nuisance.

Attempts to reuse the materials composing scrap tires have had verylimited economic success. Many of these involve destructivedistillation. The approaches to reuse, burn, or distill scrap tiresappear not to have been commercially successful and had little effect onreducing either the flow or accumulation of scrap tire carcasses.

Truck tire carcasses with acceptable sidewall structure are recapped.The original tread stock of a used truck tire is removed by buffing. Theresulting tire buffings, generated from the removal of the originaltread stock, have been the primary feedstock material for the UnitedStates tire generated crumb rubber industry. This utilization, however,is limited in its scope and does not address the problem presented byscrap passenger or truck tire carcasses no longer suitable to berecapped.

Other methods of using scrap tire carcasses have included burning tirechips for BTU value and low and high vacuum pyrolysis to recover oil,carbon black, steel and fiber.

Several methods have been employed to enhance the value of scrap tirederived crumb rubber in vulcanized curing procedures. These methods are:polymeric coatings to enhance re-manufacture in rubber goods, additionof various quantities of tall oil derived fatty acids to adhere rubberparticles into a useful mass, sulfur additions to act as a vulcanizingagent, and various complete devulcanization processes. Tire generatedcrumb rubber is also used in minimal percentages with virgin rubber as afiller and mixed with hot asphalt as a modifier.

Plastics is a multibillion-dollar industry which produces syntheticmaterials and products, many of which were never dreamed of only a fewyears ago. Today, civilization requires synthetic materials (artificialresins produced by chemical reactions of organic substances). Manyproducts made of plastic produced materials are produced at less costthan was possible with natural materials.

Plastics, unlike glass or aluminum, are not easily recycled back intouseful products, such as those which they were generated. Plastics,being a specifically engineered, rather than a generic material, aresorted prior to recycling. Plastics are seldom remanufactured back intothe product or part which generated them. Often, recycled plastics aremore expensive than new polymers. Examples of plastics which arerecycled include: (1) HDPE and LDPE into boards, bins, and trash cansand (2) PET into carpet fiber. The markets for recycled plastics havebeen slow to develop and do not appear to be able to keep pace with thegeneration of new plastic materials. Once plastics are molded or spun,they lose some of the characteristics or properties of the virginmaterial. This creates a much bigger problem than scrap tires becausethe United States generates over 12 billion tons of scrap plastics peryear, most of which is destined for deposit in landfills.

It would be desirable to develop cost feasible, raw material productsgenerated from a whole scrap tire and plastic feed stocks, involving thecrumb rubber produced from both the sidewall and tread materials.Because of the vast quantity of accumulated scrap tires and scrapplastics, it would be beneficial to broaden the market applications byforming new raw materials containing the combined properties of bothcrumb rubber and plastic.

It is well-known in the art to use tall oil with ground rubber waste forreuse as rubber. See "Ground Rubber Waste - A Supplementary Raw Materialfor the Rubber Industry" issued by Kahl & Co.; U.S. Pat. No. 4,481,335,issued Nov. 6, 1984 to Stark, Jr. entitled "Rubber Composition andMethod"; U.S. Pat. No. 3,873,482, issued Mar. 25, 1975 to Severson etal, entitled "Pyrolyzed Tall Oil Products as Synthetic RubberTackifiers"; U.S. Pat. No. 4,895,911, issued Jan. 23, 1990 to Mowdood etal, entitled "Tall Oil Fatty Acid Mixture in Rubber"; U.S. Pat. No.4,792,589, issued Dec. 20, 1988 to Colvin et al, entitled "RubberVulcanization Agents of Sulfur and Olefin"; and U.S. Pat. No. 4,224,841,issued Jan. 13, 1981 to Frankland, entitled "Method for Recycling Rubberand Recycled Rubber Product". Generally for the area of ground polymerelastomer operation, see U.S. Pat. No. 4,771,110, issued Sep. 13, 1988to Bouman et al, entitled "Polymeric Materials Having ControlledPhysical Properties and Purposes for Obtaining These"; and for rubberdiscussions see U.S. Pat. No. 3,544,492, issued Dec. 1, 1970, to Tayloret al, entitled "Sulfur Containing Curing Agents"; and "OrganicChemistry" by Fieser and Fieser printed 1944 by D. C. Heath & Co.Boston, pages 346 and 347.

SUMMARY OF THE INVENTION

The present invention is a dry liquid concentrate mixture in combinationwith organic and other components which dry liquid concentrate includesthe base combination of: the major constituent crumb rubber, generated,for example, from processing the tread or sidewall of scrap tires, and aminor constituent of tall oil, its derivatives and other fatty acids.This combination forms the dry liquid concentrate mixture capable ofacting as an impact modifier, homogenizing ingredient, extender, andviscoelastic modifier in a variety of non vulcanized cure systems forplastics and asphalt. The dry liquid concentrate mixture can alsofunction as a carrying agent for additional plasticizing orcompatibilizing chemicals to focus on specific applications.

The preferred dry liquid concentrate is a homogeneous blend of cured andshaped rubber particles that contain minimum moisture content and aliquid blend of tall oil, tall oil derivatives and other fatty acids.These liquid blends plasticize, swell, and soften the rubber particles,and allow the formation of chemical bonds between the rubber particleand asphalt, thermoplastics, thermoplastic elastomers,polyvinylchloride, polyacrylates, polyurethane coatings and binders,epoxies and other organic based compounds and is useful in thermoplasticreclamation.

The dry liquid concentrate mixture imparts elastomeric characteristicsinto the parent materials with which it is combined. Acting as an impactmodifier, it helps to improve the modulus, elongation, and tensilestrength, and changes the viscoelastic characteristics and helps toblend out crystalline spots in various high molecular weight polymers.Acting as a processing aid in polyethelylene and other polymericreclamations, it homogenizes varieties of various molecular weightpolymers together, imparting beneficial properties that even virginpolymers do not possess.

The dry liquid concentrate also adds the following captured anddispersed in the tire rubber: (1) carbon black, (2) ultra violetstabilizers, (3) heat stabilizers, (4) impact modifiers, and (5)antioxidants.

DESCRIPTIONS OF THE PREFERRED EMBODIMENT(S)

Cured rubber particles form one of the basic components of a dry liquidconcentrate mixture used in the present invention. The cured rubberparticles used are of natural or synthetic rubber, or the combinationthereof, which has been substantially vulcanized or cured, as in themanufacture of automobile or truck tires. Truck and automobile tiresconstitute the main source of available, useful cured rubber particles.With respect to tires as a source of cured rubber particles, the dryliquid concentrate mixture is equally effective on the rubber generatedfrom either the sidewall or tread of the scrap tire carcasses. Commonrubbers useful for the dry liquid concentrate of the present inventionincludes, but are not limited to: NR, SBR, isoprene, EPDM, neoprene,nitrile, butyl, and ethylene-propylene diene rubbers. There is no needto separate the rubbers by polymer content. Crumb rubber produced fromthe sidewall or tread is acceptable as a component of the dry liquidconcentrate of the present invention.

The rubber particles should be processed to be substantially free ofcontaminants, such as steel and fiber. For best results in thermallyactivated reactions, the rubber particles should contain minimummoisture content, which should be not more than 0.5% because the waterwill expand during manufacture.

    ______________________________________                                        TIRE GENERATED                                                                CRUMB RUBBER PRODUCT ANALYSIS:                                                (Whole Tire/Tread Stock Only)                                                 Product Analysis                                                                           Minimum    Maximum   Method                                      ______________________________________                                        Acetone Extract                                                                            10%/9%     19%/17%   BTM-4-07                                    Ash Content  --/--      8.0%/7.0% BTM-4-05                                    Carbon Black Content                                                                       28%/27%    39%/38%   BTM-4-10                                    Rubber Hydrocarbon                                                                         42%/45%    --/--                                                 ______________________________________                                    

Rubber particle shape and size are important elements of the rubberparticles for use with the dry liquid concentrate mixture. The varietyof processing systems designed to recover the available rubber particlesfrom scrap tire carcasses include: granulation, stone grinding, cutting,sonic impacting, cracking, and cryogenic fragmentation. These variousprocessing systems yield particles of different classes of size andshape. Granulation and cryogenic fragmentation yield particles withsimilar height, width, and depth dimensions, as well as a relativelysmooth surface. Stone grinding, sonic impacting and cracking yieldparticles with greater surface area per mesh size and rough surface moreconducive to the formation of mechanical bonds. Rubber particles,regardless of the method of production, fall into four basic shapecategories:

    ______________________________________                                        CRYOGENIC MATERIALS:                                                                             Smooth Surface                                             ABRADED MATERIALS: Rough Surface                                              TORN MATERIALS:    Rough Surface                                              CUT MATERIALS:     Smooth Surface but not as                                                     smooth as Cryogenic                                                           Materials                                                  ______________________________________                                    

The cured rubber particles maintain their memory of shape in all of theapplications of the dry liquid concentrate mixture. Functional mesh sizeis determined by application. Rough surfaces, such as flake and oblongsurfaces, of rubber particles will obtain greater mechanical bonds andadd flexibility to materials in which they are used. Smooth surfaces,such as cubic rubber particles, are effective in adding the greatestresistance to abrasion and range of temperature to materials in whichthey are used.

Tall oil agents form another of the basic components of the dry liquidconcentrate mixture used in the present invention. Tall oil agents maybe any of Unitol DP-5, commercially available from Union CampCorporation, NEO-SPANGOL T20, commercially available from Kahl & Co. andother formulations consisting of tall oil pitch, tall oil heads anddimer acid used without sulfur or a sulfur donor.

Tall oil, tall oil derivatives, and other fatty acids which fall withinthe following ranges of characteristics may be used in the dry liquidconcentrate mixture:

    ______________________________________                                        Viscosity, (centistokes at 99° C.)                                                         10 to      1000                                           Acid Number, (Total)                                                                              15 to      330                                            Saponification Number                                                                             10 to      350                                            Fatty Acids, %      5% to      100%                                           Rosin Acids, %      0% to      70%                                            Unsaponifiables     5% to      80%                                            ______________________________________                                    

Mixing of the rubber particles with the tall oil agents is bestaccomplished by a dispersion mixing system, such as a ribbon blender;mastication is not required. Mixing can be done at ambient temperature,however pre-warming the rubber particles to approximately 80° C. andintroducing of chemical agent formulations, such as the tall oilformulations, having a temperature of approximately 90° C. yield thefastest mixing cycle. Additional processing aids may also be used in thedry liquid concentrate mixture, such as, for example, pvc plasticizers,anti-strip agents for asphalt and polyethylene lubricants. These shouldbe added to the tall oil formulations prior to mixture of the tall oilwith the rubber particles. For best results, the dry liquid concentratemixture should be allowed a twenty four hour standing time prior tousage. The dry liquid concentrate mixture is hydrophobic and the normaltendency of untreated crumb rubber to accumulate air-borne moisture isreduced. For most applications a 5 to 35 part per hundred by weight mixrate of the tall oil agent-and other processing aids to the rubberparticles is sufficient.

The formulations described above will effect virtually all sizes andshapes of cured rubber particles. The physical mesh size, shape andcontent of the cured rubber particles is determined by applicationrequirements. For example, in an application of the dry liquidconcentrate mixture with thermoplastics and thermoplastic elastomers,there are constraints related to extrusion nozzle size, mold entryports, and the surface texture required on the end product. For thispurpose, cubic, smooth shaped rubber particles as additions of equalweight and mesh size have less impact on the viscosity of blends of thedry liquid concentrate mixture with such plastics and elastomers than doflake or oblong, rough particles because the particle has less surfacearea.

Plastic compounding with a dry liquid mixture can be accomplished byeither a strand extruder or an underwater pelletizer. However because oflow green strength at the extruder nozzle masterbatch, compoundscontaining a composition of greater than 25% of treated crumb rubber arebest achieved with the under water pelletizer.

Mixing of the dry liquid concentrate with parent materials other thanthermoplastic, e.g., epoxies, urathanes, asphalt, latex, etc., should bedone before application to another surface and should be accomplished byblending a quantity of the dry liquid concentrate mixture within theviscosity restraints required for the parent materials usage.

The dry liquid concentrate mixture enhances the snyergisim between thecrumb rubber and the parent material which is not accomplished withoutthe use of the tall oil, tall oil derivatives, and other fatty acids.This allows the crumb rubber particles to effectively impart theirphysical elastomeric qualities to, for example, plastics.

Other components which may be included in the dry liquid concentratemixture during the application with the parent materials for variousapplications (because these components are in the rubber) are: (1)carbon black, (2) ultra violet stabilizers, (3) heat stabilizers, (4)impact modifiers, and (5) antioxidants.

APPLICATIONS RUBBERIZED ASPHALT

The dry liquid concentrate mixture enables the use of crumb rubber as anasphalt binder modifier without the typical heat blending reactioncycle. Even dispersion of the dry liquid concentrate throughout theasphalt mixture is required. In asphalt-rubber hot mix, the dry liquidconcentrate may be added either on the dry (rock aggregate side) or wet(heated, liquified asphalt) side of the mix prior to combining. Inasphalt emulsions, the dry liquid concentrate should be meter blendedinto the emulsion, in the same manner as adding to the wet sidediscussed above.

    ______________________________________                                        GRADUATIONS OF REQUIRED GROUND                                                TIRE RUBBER (HOT MIX ASPHALT)                                                         Dense     Open      Gap      Open or                                  SIEVE   Graded    Graded    Graded   Dense                                    SIZE %  Asphalt   Asphalt   Asphalt  Asphalt                                  PASSING TYPE I    TYPE II   TYPE III TYPE IV                                  ______________________________________                                        10      100       100       95-100   100                                      16      100        75-100   --       --                                       30      70-100    25-60     0-10     25-30                                    50      --        --        0-2      5-45                                     80      0-20       0-20     --       --                                       100     --        --        --       0-10                                     200     0-5       0-5       --       --                                       ______________________________________                                        DRY LIQUID CONCENTRATE %                                                      BY WEIGHT PER ASPHALT BINDER CONTENT                                          TYPE I        17%-26%                                                         TYPE II       17%-26%                                                         TYPE III      17%-26%                                                         TYPE IV       17%-26%                                                         ______________________________________                                        CHEMICAL TREATMENT (TALL OIL                                                  FOR EXAMPLE) RATIO BY RUBBER TYPE                                             CHEMICAL TREATING AGENT %                                                     BY WEIGHT OF RUBBER                                                           TYPE I        9%-28%                                                          TYPE II       9%-28%                                                          TYPE III      9%-28%                                                          TYPE IV       9%-28%                                                          ______________________________________                                    

In summary, asphalt modification (dry or wet applications) isaccomplished with

a. Rubber particle mesh sizes from less than 10 to greater than 200depending upon application

b. Dry liquid concentrate % by weight of 9%-28% depending uponapplication of asphalt binder

After mixing the dry liquid concentrate made up as set out above withthe asphalt binder, the mixture is added to rock for paving or is usedwithout rock for crack seal and emulsions, such as for roofing material.

THERMOPLASTIC

The preferred method of utilizing the dry liquid concentrate mixture tomodify thermoplastic involves the compounding of the respectivethermoplastic with the dry liquid concentrate mixture. The preferredextruder is a twin screw system to insure proper dispersion of therespective thermoplastic with the dry liquid concentrate mixture. Asingle screw extruder may also be employed, however the feed system mustbe carefully metered to insure proper dispersion between thethermoplastic and the dry liquid concentrate. Dry mixing may also beemployed, however even dispersion of the dry liquid concentrate mixturewith the thermoplastic is required to assure part quality. The extruderis to be operated at the proper melt temperature for the variousthermoplastic relative to the specific melt index of the plastic. Theextruder temperature for most thermoplastic varieties will range between300° F. to 600° F., and preferably 375° F. to 600° F.

    ______________________________________                                        GRADUATIONS OF REQUIRED                                                       GROUND TIRE RUBBER FOR PLASTICS                                               SIEVE    Coarse   Medium    Fine    Ultra Fine                                SIZE %   Rubber   Rubber    Rubber  Rubber                                    PASSING  TYPE I   TYPE II   TYPE III                                                                              TYPE IV                                   ______________________________________                                        20       100      --        --      --                                        30        80-100  100       --      --                                        40       50-80    80-95      90-100 --                                        60        0-10    40-65     60-80   --                                        80       0-5       0-20     40-65    85-100                                   100      --       0-5       15-25   65-90                                     200      --       --        0-5     10-25                                     400      --       --        --      10-25                                     ______________________________________                                    

The fineness of the rubber particles used will depend on theapplication.

    ______________________________________                                        CHEMICAL TREATMENT (TALL OIL                                                  FOR EXAMPLE) RATIO BY RUBBER TYPE                                             CHEMICAL TREATING AGENT %                                                     BY WEIGHT OF RUBBER                                                           ______________________________________                                        TYPE I        9%-28%                                                          TYPE II       9%-28%                                                          TYPE III      9%-30%                                                          TYPE IV       9%-35%                                                          ______________________________________                                    

The percentage of dry liquid concentrate mixture of the CHEMICALTREATING AGENT Percentage Table above to thermoplastic is determined byapplication (part) requirement.

The chemical formulations of UNITOL DP-5, NEO-SPANGOL T20, and otherformulations derived from tall oil, tall oil derivatives and other fattyacids are therefore used for mixture with crumb rubber particles with amoisture content, less than 0.5%, derived primarily from the processingof scrap tires to yield a dry liquid concentrate mixture capable ofacting as an impact modifier, a viscoelastic modifier, homogenizingingredient or an extender in:

1. Thermoplastic compounding (e.g., PE, PV, PET etc.) with

a. Rubber particle mesh sizes from less than 20 to greater than 400depending on application

b. Dry liquid concentrate % by weight of 5%-85% depending on applicationof thermoplastic compounding

2. Thermoplastic coatings with

a. Rubber particle mesh sizes from less than 80 to greater than 400(Type III or IV) depending on application

b. Dry liquid concentrate % by weight of 10%-60% depending onapplication of thermoplastic coating

3. Thermoplastic elastomers with

a. Rubber particle mesh sizes from less than 20 to greater than 400depending on application

b. Dry liquid concentrate % by weight of 5%-70% depending on applicationof thermoplastic elastomers

4. Thermoplastic recycling with

a. Rubber particle mesh sizes from less than 20 to greater than 400depending on application

b. Dry liquid concentrate % by weight of 5%-70% depending on applicationof recycled thermoplastic

5. Epoxies (grouting, compounding and coatings) with

a. Rubber particle mesh sizes from less than 30 to greater than 200(Type II, III or IV) depending on application

b. Dry liquid concentrate % by weight of 5%-40% depending on applicationof epoxy

6. Coating composition made from an aliphatic urethane with 3%-60% byweight of treated rubber particles contained in the coating depending onapplication of a particle mesh size ranging from less than 30 to greaterthan 400 (Type III or IV).

The admixture of various processing aids for plastics, coatings, paints,etc. may also be used with rubber particles mixed with such tall oil,tall oil derivatives or other fatty acids where the dry liquidconcentrate mixture is used as a carrying agent for these aids, such asPVC plasticizers where the dry liquid concentrate mixture may be usedwith a PVC plasticizer before introduction in the PVC.

In all of these circumstances, the ability is provided to increase thebonding properties of, for example, cubic rubber (e.g., cryogenic), withparent materials, such as plastics.

In thermally driven applications untreated rubber particles swell,soften, and exchange oils. Because of the high specific heat index ofrubber, this usually requires an extended period of time (20 minutes to60 minutes at temperatures ranging from 300° F. -600° F. degrees inasphalt). In Block mold applications using untreated rubber, the cookingtime can be as long as 3 to 4 hours at over 400° F. to cause thisaction. Additives to the rubber may be impractical at these temperaturesdegrading the performance of the final product, such as a plastic andmay render the process uneconomical because of mold cycle time.

The use of the dry liquid concentrate mixture begins this swelling andsoftening reaction without heat. When the dry liquid concentrate isadded to parent materials, the normal heat viscosity curve, relative tothe rubber, has been reduced allowing useful incorporation into parentmaterials determined by the parent materials heat index, therebyovercoming the problems of the prior art.

EXAMPLES ASPHALT

An AC-20 asphalt may be blended with a 10-30 mesh ambiently producedcrumb rubber (Type I or Type II). The crumb rubber is blended with 12%(by weight) of Unitol DP-5™. The resulting dry liquid concentratemixture is blended into the asphalt at a temperature of 320 ° F. Thejellified material from this blending is accomplished within a mix cycleof 5 minutes, instead of the typical 30 minute cycle and normal reactiontemperature of 375° F.

An AC-30 asphalt binder may be mixed with a dense grade aggregate. Theaggregate may be premixed with the dry liquid concentrate at a rate of1.1% by weight of the dry liquid concentrate mixture to the aggregate(which for an aggregate of 92-95% by weight of the final asphalt binderand aggregate mixture thus yields 9%-28% of the dry liquid concentratemixture to the asphalt binder). The crumb rubber, prior to chemicaltreatment, would have the following sieve sizes:

    ______________________________________                                        U.S. Standard Sieve % Retained                                                ______________________________________                                        10                   --                                                       30                   50-70                                                    50                   70-95                                                    100                   95-100                                                  ______________________________________                                    

The crumb rubber is blended with 11% (by weight) of Unitol DP-5™.

The resulting lab briquette contained an asphalt binder content of 6%.The briquette showed a 17% softening as a result of the dry liquidconcentrate mixture addition, not known in the art.

THERMOPLASTIC

I. A whole tire generated ambiently may produce abraded crumb rubberwith the following pre-treatment sieve size:

    ______________________________________                                        U.S. Standard Sieve % Retained                                                ______________________________________                                        20                   --                                                       30                   20-45                                                    50                   70-90                                                    80                    95-100                                                  ______________________________________                                    

The crumb rubber may be mixed with 12% (by weight of the rubber) ofNEO-SPANGOL T-20™.

The dry liquid concentrate mixture may be dry mixed with recycled highdensity polyethylene in a 50%-50% by weight mix and injection molded innon-compounded form. A 500 ton nitrogen driven injection mold machinewas used in this example. The injection mold machine was operated attemperature of 450° to 500° F.

The resulting molded part showed even dispersion of crumb rubber withexcellent flow characteristics. Tensile was decreased by 6%, however,elongation, resistance to abrasion and the cold and hot temperatureproperties of the product were each increased by an average of 50%.

II A recycled HDPE dry liquid concentrate mixture may be prepared asfollows:

Particle Rubber Sieve Size

    ______________________________________                                        U.S. Standard Sieve % Retained                                                ______________________________________                                        10                   --                                                       30                   50-70                                                    50                   70-95                                                    100                   95-100                                                  ______________________________________                                    

The crumb rubber is mixed with Unitol DP-5™ at a weight rate of 12% ofthe Unitol DP-5 to the crumb rubber. The dry liquid concentrate mixtureis then mixed with recycled HDPE at a rate of 25% dry liquid concentratemixture to the HDPE and then compounded through a strand extruderoperating at a temperature of range of 450° F.-500° F. The resultingcompound may then be injection molded at a temperature range of 450°F.-500° F. into a part (such as a pipe thread protector). The materialshowed excellent flow characteristics, even rubber distribution, no lossin tensile strength, increased resistance to abrasion and increasedtemperature properties.

III An ambient crumb rubber sample ranging in mesh size from not less 10mesh to no greater than 50 mesh may be treated by weight with 10% UnitolDP-5™ to the crumb rubber. The dry liquid concentrate mixture may thenbe mixed with polyethylene film. The mix, by weight, would be 80% dryliquid concentrate mixture and 20% polyethylene film. The mixture may beplaced into a cubic foot mold. The mold may be closed under five tons ofpressure. The mold may then be placed into an autoclave oven and cookedat 400° F. for a period of three hours. The resulting block resembles asolid rubber unit. Core samples could be bent in half without breakingor tearing. Thus a rubber type material is produced without the need forsulphur or zinc oxide or accelerators in a non-vulcanized method whiledisposing of polyethylene film.

IV An ambient sample of crush rubber ranging from not less then 80 meshto not more than 200 mesh may be treated with a tall oil pitch, tall oilheads and dimer acid, such as Unitol DP-5™, at a 10% weight ratio to thecrumb rubber. The material may be mixed with thermoplastic copolymers ata ratio of 25% to 40% of dry liquid concentrate mixture to thethermoplastic copolymers. This mixture may then be applied with aspecially designed flame thrower, such as manufactured by PlasticFlamecoat Systems, Inc. of League City, Tex. The resulting coating wasapplied to both steel and aluminum and showed excellent properties ofadhesion. The coating was also electrically conductive.

V A cryogenic crumb rubber sample of not less than 60 mesh to not morethan 200 mesh was treated with Unitol DP-5™ at a weight of 11% of UnitolDP-5™ to the crumb rubber. The dry liquid concentrate mixture was thencompounded with virgin HDPE at a temperature range from 450° F.-500° F.The compound mix was 25% dry liquid concentrate mixture and 75% virginHDPE by weight.

The rubberized compound was then used at a 25% weight rate with virginHDPE and extruded into a 40 mil sheet. The sheet exhibited no loss oftensile strength, however exhibited greater resistance to puncture andabrasion than non-rubberized HDPE.

Accordingly, because many varying and different embodiments may be madewith the scope of inventive concept herein taught including equivalentstructures or materials hereafter thought of, and because manymodifications may be made in the embodiments herein detailed inaccordance with the descriptive requirements of the law, it is to beunderstood that the details herein are to be interpreted as illustrativeand not in a limiting sense.

What is claimed as invention is:
 1. A dry liquid concentrate mixture foruse with organic compounds in nonvulcanized curing systems for plastics,recycled plastics, thermoplastics, thermoplastic elastomers,polyacrylics, polyurethanes, asphalt, and emulsions thereof, includinglatex, comprising a uniform mixture of:a. substantially dry crumb rubberincluding cured and shaped rubber particles; b. a liquid agent takenfrom the group consisting of fatty acids and tall oil pitches within thefollowing ranges of characteristics:

    ______________________________________                                        Viscosity, (centistokes at 99° C.)                                                          10 to     1,000                                          Acid Number (Total)  15 to     330                                            Saponification Number                                                                              10 to     350                                            Fatty Acids, %       5% to     100%                                           Rosin Acids, %       0% to     70%                                            Unsaponifiables      5% to     80%;                                           ______________________________________                                    

wherein the moisture content of said rubber particles and liquid agentis not more than 0.5%.
 2. The mixture of claim 1 in which the particlesize of the cured rubber particles is finer than about 10 mesh.
 3. Themixture of claim 2 in which the cured rubber particles have a smoothsurface.
 4. The mixture of claim 2 in which the cured rubber particleshave a rough surface.
 5. The mixture of claim 1 wherein there is furtherincluded PVC plasticizers.
 6. The mixture of claim 1 wherein about a 5to 30 part per hundred by weight of liquid agent to cured rubberparticles is used.
 7. An improvement in treating compounds innonvulcanized cure systems formulations that do not cure rubber or usesulfur or sulfur donors to crosslink, comprising incorporating into saidcompounds prior to curing a uniform mixture of:a. substantially drycured and shaped rubber particles which have no more than 0.5% moisturecontent; b. a liquid agent taken from the group consisting of fattyacids and tall oil pitches within the following ranges ofcharacteristics:

    ______________________________________                                        Viscosity, (centistokes at 99° C.)                                                          10 to     1,000                                          Acid Number (Total)  15 to     330                                            Saponification Number                                                                              10 to     350                                            Fatty Acids, %       5% to     100%                                           Rosin Acids, %       0% to     70%                                            Unsaponifiables      5% to     80%;                                           ______________________________________                                    

wherein the moisture content of said rubber particles and liquid agentis not more than 0.5%.
 8. A method of enhancing the cure of a compoundselected from the group consisting of asphalt, plastics, thermoplasticelastomers, thermoplastics, epoxys, and polyurethanes which comprisesadding a mixture of substantially dry cured and shaped rubber particlesand a liquid agent taken from the group consisting of fatty acids andtall oil pitches within the following ranges of characteristics:

    ______________________________________                                        Viscosity, (centistokes at 99° C.)                                                          10 to     1,000                                          Acid Number (Total)  15 to     330                                            Saponification Number                                                                              10 to     350                                            Fatty Acids, %       5% to     100%                                           Rosin Acids, %       0% to     70%                                            Unsaponifiables      5% to     80%;                                           ______________________________________                                    

wherein the moisture content of said rubber particles and liquid agentsis not more than 0.5%.
 9. A method for utilizing rubber scrap to yield afinal product with non-rubber compounds material taken from the groupconsisting of asphalt, thermoplastics, thermoplastic elastomers,polyvinyl chloride, polyacrylates, polyurethanes and epoxys, comprisingthe steps of:(1) preparing a dry liquid concentrate mixture byintimately mixing together substantially dry cured, shaped rubberparticles and a liquid agent taken from the group consisting of fattyacids and tall oil pitches within the following ranges ofcharacteristics:

    ______________________________________                                        Viscosity, (centistokes at 99° C.)                                                          10 to     1,000                                          Acid Number (Total)  15 to     330                                            Saponification Number                                                                              10 to     350                                            Fatty Acids, %       5% to     100%                                           Rosin Acids, %       0% to     70%                                            Unsaponifiables      5% to     80%;                                           ______________________________________                                    

wherein the moisture content of said rubber particles and liquid agentsis not more than 0.5%; (2) mixing said dry liquid concentrate mixturewith a non-rubber compound the material to form a uniform resultantmixture; (3) treating the resultant mixture with heat energy to yield aproduct.
 10. The method of claim 9 where step (1) includes mixing saidrubber particles and liquid agent at a temperature above ambient. 11.The method of claim 10, wherein said temperature is at least 80° C. forsaid rubber particles and at least 90° C. for said liquid agent.
 12. Themethod of claim 9, wherein about a 9 to 28 part per hundred by weight ofliquid agent to cured rubber particles is used, the material is asphalt,and about 17 to 26 part hundred by weight of dry liquid concentratemixture to asphalt is used.
 13. The method of claim 9, wherein about a 5to 35 part per hundred by weight of said liquid agent to cured rubberparticles is used, the material is taken from the group consisting ofthermoplastics and thermoplastic elastomers, and about a 5 to 85 partper hundred by weight of dry liquid concentrate mixture tothermoplastics and thermoplastic elastomers is used.
 14. The method ofclaim 13, wherein said resultant mixture is extruded at a temperature ofabout 300° F. to 600° F.
 15. The method of claim 14, wherein saidtemperature range is between 375° F. to 600° F.
 16. The method of claim15, wherein said thermoplastic is a thermoplastic coating and the dryliquid concentrate mixture to thermoplastic coating ratio is about in arange of 10% to 60% by weight of dry liquid concentrate mixture.
 17. Themethod of claim 15, wherein said thermoplastic are thermoplasticelastomer and the dry liquid concentrate mixture to thermoplasticelastomer ratio is about in a range of 5% to 70% by weight of dry liquidconcentrate mixture.
 18. The method of claim 15, wherein saidthermoplastic is a recycled thermoplastic and the dry liquid concentratemixture to recycled thermoplastic ratio is about in a range of 5% to 70%by weight of dry liquid concentrate mixture.
 19. The method of claim 9,wherein about a 9 to 28 part per hundred by weight of liquid agent tocured rubber particles is used, the material is an epoxy, and about a 5to 40 part per hundred per weight of dry liquid concentrate mixture toepoxy is used.
 20. The method of claim 9, wherein about a 9 to 28 partper hundred by weight of liquid agent to cured rubber particles is used,the material is a polyurethane, and about a 3 to 60 part per hundred byweight of cured rubber particles to polyurethane is used.
 21. The methodof claim 9, wherein step (1) includes mixing the liquid agent with PVCplasticizers.